View Javadoc

1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  
20  package org.apache.hadoop.hbase;
21  
22  import java.io.IOException;
23  
24  import org.apache.hadoop.hbase.classification.InterfaceAudience;
25  import org.apache.hadoop.hbase.classification.InterfaceStability;
26  
27  /**
28   * Coprocessor interface.
29   */
30  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
31  @InterfaceStability.Evolving
32  public interface Coprocessor {
33    int VERSION = 1;
34  
35    /** Highest installation priority */
36    int PRIORITY_HIGHEST = 0;
37    /** High (system) installation priority */
38    int PRIORITY_SYSTEM = Integer.MAX_VALUE / 4;
39    /** Default installation priority for user coprocessors */
40    int PRIORITY_USER = Integer.MAX_VALUE / 2;
41    /** Lowest installation priority */
42    int PRIORITY_LOWEST = Integer.MAX_VALUE;
43  
44    /**
45     * Lifecycle state of a given coprocessor instance.
46     */
47    enum State {
48      UNINSTALLED,
49      INSTALLED,
50      STARTING,
51      ACTIVE,
52      STOPPING,
53      STOPPED
54    }
55  
56    // Interface
57    void start(CoprocessorEnvironment env) throws IOException;
58  
59    void stop(CoprocessorEnvironment env) throws IOException;
60  
61  }